1. Field of the Invention
This invention relates to an improved combination of a power transmission belt that is adapted to be operated in an endless path and a tensioner for such belt.
2. Prior Art Statement
It is known in the art to provide a combination of a power transmission belt that is adapted to be operated in an endless path and a tensioner for the belt, the tensioner comprising a support means fixed relative to the belt, a belt engaging means carried by the support means and being movable relative thereto, and mechanical spring means operatively associated with the support means and the belt engaging means urging the belt engaging means relative to the support means in a belt tensioning direction and against the belt with a force to tension the belt.
Examples of combinations of the above mentioned type are provided in the following seven U.S. patents:
(1) U.S. Pat. No. 3,413,866--Ford; PA0 (2) U.S. Pat. No. 3,974,708--F'Geppert; PA0 (3) U.S. Pat. No. 4,108,013--Sragal; PA0 (4) U.S. Pat. No. 4,145,934--Sragal; PA0 (5) U.S. Pat. No. 4,151,756--Binder et al.; PA0 (6) U.S. Pat. No. 4,249,425--Watson; PA0 (7) U.S. Pat. No. 4,270,906--Kraft et al.
It appears from item (1) above that a tension spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (2) above that a "Negator" spring urges an idler pulley in tensioning engagement against a belt, the "Negator" spring providing a substantially constant urging force throughout the permissible range of idler pulley positions.
It appears from item (3) above that a compression spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (4) above that a leaf spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (5) above that a plurality of bi-metal dish-shaped springs or spring washers are disposed in various stacked relations thereof and urge an idler pulley in tensioning engagement against a belt.
It appears from item (6) above that pneumatic means is adapted to threadedly adjust an idler pulley rod of a belt tensioner wherein a pair of dish-shaped springs or spring washers urge the idler pulley in tensioning engagement against a belt.
It appears from item (7) above that a plurality of dish-shaped springs or spring washers are disposed in stacked compressed relation to urge a cam member to cam an idler pulley in tensioning engagement against a belt.
It is also known to provide a combination of a power transmission belt that is adapted to be operated in an endless path and a tensioner for the belt, the tensioner comprising a support means fixed relative to the belt, a belt engaging means carried by the support means and being movable relative thereto, and mechanical spring means operatively associated with the support means and the belt engaging means urging the belt engaging means relative to the support means in a belt tensioning direction and against the belt with a force to tension the belt, the spring means comprising a plurality of spring washers disposed in a stack thereof. The tensioner has compressing means compressing the stack of spring washers between the support means and the belt engaging means to provide the urging force on the belt whereby each spring washer is deflected between its inner periphery and its outer periphery by the compressing means.
For example, see aforementioned items (5), (6) and (7).